Telephone-exchange system.



C. W. KECKLER.

TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED JUNE 30. 1911.

Tr/ Se) Pdtented. Mar. 12,1918.

Char/e5 W ffec/r/en CHARLES W. KECKLER, OF NEWARK, NEW JERSEY, ASSIGNOR T0 CVESTEIIELILNT ELECTRIC 1 COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

. Application filed June 30,1917. Serial no, 177,916. a

To all whom it may concern:

Be it known that I, CHARLES W. KECKLER, a citizen of the United States, residing at Newark, in the county of Essex'and State of New Jersey, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems, and morep-articularly to such systems in which connections are estab- V lished between telephone lines terminating at different switchboards. I

In such .systems in establishing. connections between local and toll lines, it is usual for the local operator when receiving a call for a toll line to connect the calling line with a trunk circuit extending to a recording operator, who then finds out from the calling subscriber, the number or name of the desired party and fills out a toll ticket giving the proper instructions to the toll operator. This ticket is then forwarded to the toll operator, and the recording operator upon disconnecting from the recording trunk circuit, causes a signaling device of the local link circuit to furnish to the originating operator a characteristic signal, commonly known as a peremptory disconnect signal. The local or originating operator thereupon disconnects the link circuit from the recording trunk circuit and the calling line. The connection between the'calling local and the wanted toll line is then built up under direction of the toll operator upon receipt of the toll ticket.

Systems of this character heretofore employed have been in connection with local and toll switchboards located in the same office or in separate oflices situated near each other. Where the boards are so situated it is economical to employ a three conductor recording trunk circuit between the boards and to control the peremptory disconnecting signal over the third conductor which is separate and distinct from the two conductors forming the talking circuit. However, when the two switchboards are located quite a distance apart, for example, severalmiles, it is not economical to provide theextra or third conductor for the trunk circuit, and it becomes necessar to use the two talking conductors only an tory disconnecting signal over these conductors. .Also since a toll connection into control the perempvolyeslexpensive toll lines and equipment, whlch 1t 1s necessary at all times to maintain in good working order, it is desirable to Specification of Letters latent. Patented BT31, 12,1918.

have allcontrol apparatus located at or near the toll board where it can be centralized and be available for use with one or more of several trunk circuits extending to different local switchboards located in different ofiices. It is, therefore, the object of this invention to provide a system of this character in which the desirable features above set forth are realized.

For a more complete understanding of this invention reference should be had to the following description considered in connection with the accompanying drawing contalning one embodiment thereof.

In the drawing there is shown a recording trunk circuit A, extending from a local or originating operators position of a switchboard X, to a recording operators desk or switchboard Y. At the local switchboard X, there is a cord circuit B, which may be employed in'connecting a calling subscribers line D with the recording trunk circuit A. At the recording operators desk Y, there is located a cord circuit C, by means of which the recording operator may answer calls over and connect the telephone set with the recording trunk circuit.

Assuming that the operator at the local switchboard X receives a call for a toll line, the plug 3 of the cord circuit B is immediately inserted in the jack 4 of'the recording trunk circuit A, whereupon calling supervisory lamps is lighted and relay 6 is operated. When both windings of relay 6 are connected in circuit with the winding of supervisory relay '7, the supervisory relay doese not operate, but does operate when the ri ht-hand winding of relay 6 is short-cir cuited. The operatlon of relay 6 causes lamp 8 to be lighted over a circuit from battery through the lamp 8, contact 9 of relay r 10, contact 11 of relay 12, and the contact 'of relay 6 to ground. The recording opergization of relay 12. The energizing circuit for relay '12 may be traced from battery through thewinding of relay 12, contact 18 of relay 10, and the contact of relay 6 to ground. Relay 12, upon energization, completes av locking circuit for itself through contactl lthereof and the contact of relay 6. The operation of relay 10 also closes its contact 19 thereb i short-circuitin the ri 'hthand winding of relay 6, whereupon the supervisory relay 7 is'operated to complete for the calling supervisory lamp '5 a shunt circuit i-i'i'cluding resistance 20. This lamp is thereby etlaced. Relay 12, in operating, removes battery supply from the talking strands 21 and 22 of the trunk circuit. At the time relay 10 is operated, its contact 23 is closed, causing the operation of a slow release relay 24, which, in operating, opens its contact 25, thereby preventing the Open a'tion'of relay 26 upon the energi'zation of relay 12.

After the recording operator has received all necessary information from the calling subscriber, the plug'oit-th'e cord circuit C ma be withdrawn from the jack 16,whereupon relays 10 and 24 release. Since relay 12 is now locked up, the release of relay 2% Y 7 causes the operation of relay 26 over a circreased and decreased.

cuit from battery "through the winding of relay 24, contact 25 thereof, winding of re lay 26, upper alternate contact of relay 12, and the upper Winding of the retardation coil 27 to ground. The resistance of relay 26 is such that when in circuit with relay 24, relay 241 does not receive *suflicient current to cause it to attract its armature and open its contact 25. The operation of relay 26 opens its normal and closes its alternate contact, whereupon an intermittent energizing circuit for relay 10 is completed from battery through interrupter 30, right=hand winding of relay 10 and the alternate contact "of relay 26 to ground. Relay 1G is thereby successively energized and deenergized as longas the alternate contact of relay 26. is closed. This encrgization and deenergi'zation of relay 10 causes the intermittent closure of its contact 19, whereby through the intermittent 'short=circuiting oi the right-hand winding of relay 6,the flow of current over the talking circuit-0f the recording trunk circuit is successively in- Supervisory relay 7 is'therefore successively energized and deenergized and as a result thereof, calling supervisory lamp '5 intermittently lighted to furnish a peremptory discon'ect signal. The local operator upon observing this disconnect signal immediately disconnects "the cord "circuit 13 from the-calling line andthe recording trunk circuit. 'Upon the Withdrawal of the plug 3 from the jack 4, relay 6 releases, thereby opening the locking circuit the talking -'co nductors 21 and 22, whereupon relay 31 in the herd circuit *O'o rates to light lamp Upon-the reinsertion of the plug 3 in the jack 4, relay 6 operates, establishi-ng an energizing circuit for relay 12, Which then attracts its armatures, disconnecting battery from the talking conductors,

whereupon the relay '31 releases to extinguish the lamp Each time that the plug 3 is withdrawn from jack i, the lamp 32 will light, thereby furnishing a recall signal to the recording operator.

Should the recording operator for any reason desire to attract the attention of the local operator, the momentary withdrawal oftheplug 1-5 from jack 16 will cause themeinentary lighting of the lamp 5. This is effected through the release of relay 10 when the plug 15 is withdrawn from jack 16. hen relay 10 releases, the short circuit of the right-hand Winding of relay 6 is removed, whereupon relay 7 releases, removing the shunt from lanip 5, which thereupon lights. Since relayfla is slow in releasing, it does not release its armature during the momentary removal of the plug 15 from the jack 16. Upon the reinsertion of the plug 15 into jack 16, relay 10 is again operated, whereupon lamp 5 is' effaced in the manner herein described. 7

What is claimed is: 7

'1 In a "telephone exchange s'ystennItho combination of a trunk circuit extending from a-first to a second switchboarrha link circuit at each s'w' itchb'oard connected with the trunk circuit, a signaling device at the int switchboard individual to the link circuit ther'eat, a source of current connected with the talking circuit, switching mecha nism located at the second switchboard rendered efie'cti've uponthe di'sconnection of the link circuit 'thereat "from the trunk circuit for intermittently varying-the flow of current over the talking circuit, and a relay at the first switchboard responsive thereto for signaling device. 1 1

2. In a 'telephon'e exchange system, the combination "of a trunk "circuit comprising a two-conductor talking circuit extending causing the intermittent operation of the from a "first to a second switchboard, a link nism located at the second switchboard rendered effective upon the disconnection of the link circuit thereat from the trunk circuit for successively increasing and decreasing the flow of current over the talking circuit, and a relay at the first switchboard responsive thereto for causing the intermittent oporation of the signaling device. v 3. In a telephone exchange system, th combination of a trunk circuit comprising a two-conductor talking circuit extending from a first to a second switchboard, a link circuit at each switchboard connected with the trunk circuit, a signaling device at the first switchboard associated with the link circuit thereat, a source of current connected with the talking circuit, interrupter mechanism at the second switchboard, a relay responsive to the disconnection of the link circuit at the second switchboard from the trunk circuit for including the interrupter mechanism in operative relation to the talking circuit thereby to increase and decrease successively the flow of current thereover, and a relay at the first switchboard responsive thereto for causing the intermittent operation of the signaling device.

4. In a telephone exchange system, the combination of a trunk circuit comprising a two-conductor talking circuit extending from a first to a second switchboard, a link circuit at each switchboard connected with the trunk circuit, a signaling device at the first switchboard associated with the link circuit thereat, a source of current connected with the talking circuit, a relay at the second switchboard connected in the talking circuit, interrupter mechanism thereat, a relay responsive to the disconnection of the link circuit at the second switchboard from the trunk circuit for causing the interrupter mechanism to intermittently short-circuit a portion of the winding of the first mentioned relay, and a relay at the first switchboard responsive to the resulting increased and decreased flow of current in the talking cir- 'cuit for causing the intermittent operation ofthe signaling device.

5. In a telephone exchange system, the combination of a trunk circuit comprising a two-conductor talking circuit extending from a first to a second switchboard, a link circuit at each switchboard connected with the trunk circuit, a signaling device at the first switchboard associated with the link circuit thereat, a source of current connected with the talking circuit, a pair of relay I windings at the second switchboard connected in the talking circuit, interrupter mechanism thereat, a relay responsive to the disconnection of the link circuit at the second switchboard from the trunk circuit for causing the interrupter mechanism to intermittently short-circuit one of the pair of relay windings, and a relay at the first switchboard responsive to the resulting increased and decreased fiow of current in the talking circuit for causing the intermittent operation of the signaling device.

6. In a telephone exchange system, the

. combination of a trunk circuit comprlslng a two-conductor talking circuit extending from a first to a second switchboard, a link circuit at each switchboard connected with the trunk circuit, a signaling device at the first switchboard associated with the link circuit thereat, a source of current connected with the talking circuit, a relay at the second switchboard responsive to the disconnection of the link circuit thereat from the trunk circuit, interrupter mechanism and a second relay at the second switchboard, an operating circuit for the second relay including the interrupter mechanism completed upon the response of the first relay, a air of relay windings at the second switchboard connected in the talking circuit, one of which is intermittently short-circuited by the intermittent operation of the second relay, and a relay at the first switchboard responsive to the resulting increased and decreased fiow of current in the talking circuit for causing the intermittent operation of the signaling device. a

In witness whereof, I hereunto subscribe my name this 27th day of June, A. D., 1917.

CHARLES W. KECKLER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. (3.! 

